Question

which organism has an exoskeleton
deer
crab
elephant
tree

Explanation:

An exoskeleton is an external skeleton that supports and protects an animal's body. Crabs are arthropods, and arthropods have exoskeletons made of chitin. Deer and elephants are vertebrates with endoskeletons (internal skeletons). Trees are plants and do not have skeletons.

Answer:

crab